IMPACTS OF LAND USE LAND COVER ON SURFACE RUNOFF: A CASE STUDY OF UPPER MALAPRABHA BASIN

Abstract

The main efforts of this study is to understand the land use land cover change impacts on the runoff. Land use land cover impacts on the basin hydrology can be assessed by combining the influence of land use land cover changes on water resources in the catchment. The study was carried out on Upper Malaprabha Basin. Remote sensing and geographic information system technologies proved to be a very effective means of detecting the changes in land use land cover patterns. ArcMap 10.1 is used as the user interface for detecting the changes by the process of image classification. The image classification was carried out for the years 2002 and 2009. The results of image classification reflected that the forest area decreased by 49.4%, water bodies have seen raise of 1.6%, urban settlements increased by 57.1%, agriculture lands have also increased by 25.8%. Whereas the agricultural plantation and barren land have declined by 97% and 51.7% respectively. To study the impacts of the above land use land cover changes on runoff the Soil and Water Assessment Tool (SWAT) model was used. The simulation was carried out for the study area incorporating the prepared LULC maps. The calibrated and validated model reflected the R2 value to be above 0.7 and proved to be satisfactory. The average runoff in the years 1992 to 2002 was 38 m3 /sec and for the years the average runoff was 30.4 m3 /sec. The average flow trends reflect that there is decrease of about 7.6 m3 /sec in runoff. The reasons for decrease in runoff is majorly due to increase in agriculture area, water body and decrease in barren lands